This invention relates in general to load carrying devices and more particularly to an apparatus for lifting and transporting a piano.
Piano moving under current practices is an awkward, difficult and dangerous procedure. Normally, a piano is lifted off the ground manually and placed on a dolly or a wheeled platform for transporting from one location to another. At the new location, the piano is lifted off the dolly by hand and lowered to the ground. Since average pianos weigh 500 lbs. or more, lifting a piano on and off a dolly is an arduous procedure that requires several strong people. Individuals moving their household goods from place to place must often call for a special crew of laborers just to move their piano for them at a considerable extra expense. Businesses such as musical instrument stores and piano sales and rental outlets must employ extra laborers solely for the purpose of moving pianos. The currently utilized procedure carries a substantial danger of injury to the work crew and to the piano itself. Workers can strain and injure their back while lifting a piano. The piano and dolly are unstable while a piano is being lifted onto the dolly and can tip or fall over. Moreover, the piano being transported on a dolly is exposed on all sides to damage from contact with objects such as sharp corners. Even a small scratch or scrape on a polished finish of a piano can substantially reduce its value.
Additionally, pianos are often tuned at a store before they are delivered to a buyer, and considerable care should be taken not to incline the piano to such a degree as to permit it to be out of tune when it arrives at its final destination in the buyer's house.
A combination of a dolly structure and lifting means for raising and transporting objects relative to a horizontal surface is known from, for example, U.S. Pat. No. 1,101,217 issued to Stamm which discloses a burial apparatus for engaging, raising and lowering a casket and for transporting a casket above the ground; from U.S. Pat. No. 3,191,787 issued to Starn and U.S. Pat. No. 2,333,208 issued to Spear which disclose means of grasping, lifting and transporting pipe sections, U.S. Pat. No. 3,973,754 issued to Chadwick which discloses a device for transporting heavy electrical equipment such as transformers, and U.S. Pat. No. 4,050,587 issued to Moen which discloses a hoist and dolly apparatus for lifting and transporting objects of various sizes, shapes and weights.
The task of lifting and transporting a piano involves several specific problems that are not addressed by the above-mentioned patents. First of all, because a piano is a highly polished and finished piece of furniture, it should only be grasped, held or hooked on a few specific parts of its frame designed for that purpose. A piano cannot be lifted straight up from the top, front, or side because a lifting mechanism attached to the piano at those points would scratch the finish. The most accessible point for lifting by on a hoisting cable is a horizontal frame post at the rear of the piano. The problem is that this hooking point is off centered from the center of gravity of the piano so that if the piano is lifted by a hook attached to the horizontal frame post, the point where the hook is attached will act as a pivot point and the bottom rear of the piano will swing inward and the top front of the piano will swing outward around that point, causing a pendulous movement of the piano, which may cause mistuning of a piano. Further, a piano that is moved from one place to another is commonly moved indoors, often through narrow doorways, hallways and other passageways. Therefore, a lifting and transporting device for a piano must conform substantially to the dimensions of the piano in its length and width and not protrude substantially beyond the dimensions of the piano.